Specifications

AUTOSTAR CCD PHOTOMETRY 75
Coefficient Determination
Determining α and ζ
vi
A plot of ((V – I) – (v– i)
o
) versus (V– I) has the slope (1 – 1 / α)
and intercept ζ
vi
/ α, from which the values for α and ζ
vi
can be
calculated. This may seem like a strange technique to find the
coefficients, but it maximizes accuracy and makes the independent
variable a known standard value. The slope (1 – 1 / α) has a value
near zero and can be determined more accurately than the simple
slope α.
Table E-7 lists the data and Figure E-3 shows a plot of the data.
The equations are in the form of an equation for a straight line:
((V – I) – (v– i)
o
) = (1 – 1 / α) * (V – I) + ζ
vi
/ α
Table E-7. ((V – I) – (v– i)
o
) versus (V– I) Data.
(V–I) – (v – i)
0
(V – I)
1.1727 -0.0680
1.1546 1.3510
1.2210 0.9040
1.2663 0.5580
1.1983 0.6500
1.2964 0.5750
1.1573 0.6590
1.1905 1.0550